The current state of the art in online search engines is highly advanced in its ability to retrieve documents that are responsive to the terms of a query. The infeasibility of charging users for each search has lead search engine providers to rely on revenue from advertisers in order to fund the search services. Advertisements have historically been placed on various parts of the search engine interface, including as banner ads, and paid inclusion links, and sidebar ads. These advertisements are typically selected in response to the particular terms of the user's query. The underlying assumption of this model is that the query terms reflect the user's interests, and thus selecting advertisements based on the query terms should yield advertisements for products or services the match these interests. Of course, advertisers generally desire to provide ads to those users who would be interested in their products or services. Thus, if the user's query is “MP3 players”, then the assumption is that the user is interested in learning about, and potentially purchasing an MP3 player, and hence an advertisement for a particular MP3 player may result in the user's purchase. The current state of the art for such advertisements is the use of pay-for-performance advertisements, in which the advertiser pays the search engine provider for placement of the advertisement on the search results page only if the user selects (clicks on or activates) the advertisement.
The problem with query driven advertisements is in the underlying assumption that the current query best expresses the user's interests. This assumption is made because the query is the only information that the search engine has about the user, and thus the only basis on which to determine the user's interests. However, a query is only a very transient and unreliable indicator of a user's underlying interests. A user may search for all manner of information, and much of the time this may be for business, technical, scientific or other information entirely unrelated to the user's actual personal interests, which the advertiser is typically trying to reach.
Thus, there is a need for a mechanism by which search engine providers can target advertisements on their search engines the personal interests of a user.